In prior art it is known how to change focal distance, magnification etc. of optical systems or lens attachments. Traditionally this is achieved either by moving at least one or a plurality of lenses in the system or by changing one or several lens shapes in the optical system, as known to a person skilled in the art.
However, mechanical movements in optical systems usually needs relatively large mechanical swings which are contrary to the needs of many modern applications of optical systems, for example as used in mobile phones, small handheld cameras, web cameras in portable computers etc. These systems must be compatible with micro system requirements as known to a person skilled in the art. Moving lenses needs relatively large movements which is a disadvantage especially when related to micro systems. There are also examples in prior art of continuous tuneable lenses, for example tuneable lenses using electro wetting or liquid crystal lenses. Typically, these systems need high driver voltages, however the range of optical power is limited and the optical aberration is changing when changing optical power of the optical system.
Other examples of optical systems that can provide OPS functionality is disclosed in U.S. Pat. No. 6,897,995, for example. A Tuneable Diffraction Grating (TDG) optical switch is disclosed that can switch light on and off. However, such devices are usually difficult to adapt to lens systems in a micro optical system and/or lens attachment.
Therefore, there is a need in the prior art for an OPS system that can switch relatively high optical effects with small mechanical movements and at the same time is not changing substantially optical parameters (for example aberration) of a lens system wherein the OPS is being used, and that the OPS is also adaptable to optical micro system needs.
Hence, an improved OPS device would be advantageous, and in particular a more efficient and/or reliable OPS device would be advantageous.